Patellar dislocation occurs when the patella moves out of its natural position by sliding outside the femoral trochlea. This can happen following a direct impact to the patella or during a sudden turn and twist of the knee. During this dislocation, the medial patellofemoral ligament (MPFL) ruptures. Sometimes, the dislocated knee cap will sometimes correct itself. An initial episode of dislocation generally does not require surgical intervention. However, if it is associated with a large cartilage lesion or a fracture, surgery is often necessary.
There are several risk factors for recurrent dislocation and the development of femoro-patellar instability: young age, femoral dysplasia (a flattened femur), patella alta (a high-riding patella), valgus alignment of the lower limbs (knock-knees), and rotational abnormalities.
In the case of recurrent dislocation, or if the patient develops a feeling of patellar instability, surgery to stabilize the patella and reconstruct the medial patellofemoral ligament (MPFL) is indicated, and if necessary, a bony correction may also be performed.
There are several risk factors for recurrent dislocation and the development of femoro-patellar instability: young age, femoral dysplasia (a flattened femur), patella alta (a high-riding patella), valgus alignment of the lower limbs (knock-knees), and rotational abnormalities.
In the case of recurrent dislocation, or if the patient develops a feeling of patellar instability, surgery to stabilize the patella and reconstruct the medial patellofemoral ligament (MPFL) is indicated, and if necessary, a bony correction may also be performed.
